Airhead Neutral Switch Leak Fix Thread

Background: New neutral switch installed as part of tranny rebuild. Leave on long trip. 5,000 miles into trip, oil starts leaking onto ledge beneath tranny. Figured it was the rear main seal that I just replaced - figured I f**ked up the install. Oh well, now home and pulled the tranny to get ready to pull clutch assembly to change rear main seal when I notice that it looks DRY up there - doesn't look like an engine oil leak!? Where could this oil be coming from....

Eventually put it all together: it was tranny oil leaking from the nuetral switch (might explain why shifting has slowly been getting notchier!)

Called Tom Porter and he explained that it was just what happens to these crappy switches. He suggested that since the tranny is already out to put in a new one - and he is sending me one no charge.

There have been some people here that have claimed to use JB weld to seal the switch and I am going to try to do something like this with the new switch before installing it. My thought is to tape (mask off) the two contacts, the threads, and the swtich assembly and then coat everything in a layer of JB Weld. I'll take some pics and report back...

Has anyone got any tips, pictures, or suggestions to doing this right?

Nope. The plan is to tape up and cover the two electrical contacts, the threads, and the switch assembly to keep the JB weld off of those areas, then bath the rest of the unit in a layer of JB, then remove the tape exposing the clean parts that were covered...

I saw you mention threads in the taping off list but couldn't make any sense of it. I thought I read that wrong. alright, eagerly awaiting the pics!

Why not just put the switch in, regular-like.... can't believe that they fail so regularly.... maybe that one got torqued a bit much, or dropped on the floor, or....??

Click to expand...

Datchew told me they just go bad--no damage required. Like Readymeal said, the heat cycles I guess eventually cause a slow drip. My oil switch did that. Luckily I got around to breaking my neutral switch the good ol' fashioned way before it had a chance to fail

In my experience, they usually last several tens of thousands of miles before crapping out or leaking. Oh well.... Maybe it's todays parts thats the problem!

Also... Installing a new one really isnt a bik deal if you have a lift.

Jack the lift up.
Drain the trans lube.Pull the rear mount 80% of th way out.
Pull out the engine mount tube.
Remove/install the new switch.
Put everything back theway it was.

I'd say 30 minutes should do!

Click to expand...

Do I feel like a jackass or what.... NEVER occurred to me when I had to put on the new wire harness.... I was using needle nozes, fat fingertips and choice words....Oh, well, any day that you learn something new is a day for the better... thanks for the "brainy" tip!@

when I put my clutch back in I used a claw hammer to pry against that tube to compress the clutch spring enough to get the lower flywheel bolts in. I thought that 'spacer' was part of the engine! Apparently the hammer thought so too because it didn't budge. Wiser heads told me to sand that tube down just enough so that it's hard to get in with my bare hands but not impossible just for the purpose of doing what mymindsok said--change out the neutral switch without pulling the whole gearbox.

I roughed two small kerfs onto the spacer as well to give me that much more line-em-up to aid insertion. Also keeping the piece in the freezer while youre doing the swap really helps get it back in. That actually makes it too easy, sometimes, so I make sure to forget whether I needed one or two washers to make it actuate properly until after I've put it in.

Also those switches live a hard life suspended upside down in hot oil and occasionally zapped with electricity I'm not surprised they weep.

Alas, no lift. Instead, I have a small piece of leftover carpet that I put down on the garage floor to lie on when I have to get under the bike.

There are so many oil drips on my garage floor, incidentally, that it looks like a Jackson Pollock painting.

Anyway, from what I've read elsewhere, the procedure, with the bike on the centerstand, is to remove the giant bolt that goes through the frame and through that aluminum spacer that blocks access to the switch. The bolt is tapped out or drawn out using the threads on one end of the nut and a succession of random washers, spacers, etc, the idea being to add spacers by increments and use the nut and threads to pull the thing out.

On my bike, at least, that bolt goes through a band that holds up the exhaust, through the forward part of the foot peg bracket, through the frame, through an extension on the bottom of the tranny casing, then through the spacer, on both sides. My fear is that I'll take the bolt out and the whole bike will fall into a random heap of parts, but those who have done it say, "Fear not." Some block up the engine but other say this isn't necessary. I'll block it up.

Prying out the spacer, apparently, is a grim ordeal involving muscle and leverage, but not too much. The switch is easily replaced, but apparently there are two, the old and the new, that are not electrically interchangeable, so you have to be sure to get the right one.

I like the idea of grinding down that spacer a tad to get it back in a little more easily, but maybe there's a good engineering reason why it's so tight. I'd hate to grind off a fraction of a millimeter and induce some kind of spacer-related death wobble. Again, from what I've read elsewhere, it can be tapped back into place as is with a plastic or wooden mallet. Then the giant bolt goes back through. It is to be tightened it in increments, going from side to side.

What the torque numbers are for the switch and the giant bolt, I'll have to find out. Does anyone know?

Also, does anyone know if the neutral switch iuntil fall s exposed during the partial dis assembly required for an in-the-frame spline lube? If that's the case, I'll just add a little gear oil and park on newspaper until fall when I plan to lube the splines.

I replaced the oil-light swith last year, which was very easy, but I suspect the neutral switch is of a somewhat similar design. I couldn't tell whether the leak was through the wires or around the edge of the hard plastic sealant. In any case, the switches are old and exposed, so it figures they'd eventually give out.

Speaking of which, my bike will turn over 100,000 kilometres this tank of gas. The last 6,000 are mine.

I've had to replace a few of these things as well. Expensive little buggers, and something of a pain. Someone mentioned ditching the switch and screwing in a plug instead. I kinda like that idea - sure would simplify things, and one less thing to go bad.

Hell, why do we need a stinkin switch to tell us if we're in neutral anyway???

Alas, no lift. Instead, I have a small piece of leftover carpet that I put down on the garage floor to lie on when I have to get under the bike.

There are so many oil drips on my garage floor, incidentally, that it looks like a Jackson Pollock painting.

Anyway, from what I've read elsewhere, the procedure, with the bike on the centerstand, is to remove the giant bolt that goes through the frame and through that aluminum spacer that blocks access to the switch. The bolt is tapped out or drawn out using the threads on one end of the nut and a succession of random washers, spacers, etc, the idea being to add spacers by increments and use the nut and threads to pull the thing out.

On my bike, at least, that bolt goes through a band that holds up the exhaust, through the forward part of the foot peg bracket, through the frame, through an extension on the bottom of the tranny casing, then through the spacer, on both sides. My fear is that I'll take the bolt out and the whole bike will fall into a random heap of parts, but those who have done it say, "Fear not." Some block up the engine but other say this isn't necessary. I'll block it up.

Prying out the spacer, apparently, is a grim ordeal involving muscle and leverage, but not too much. The switch is easily replaced, but apparently there are two, the old and the new, that are not electrically interchangeable, so you have to be sure to get the right one.

I like the idea of grinding down that spacer a tad to get it back in a little more easily, but maybe there's a good engineering reason why it's so tight. I'd hate to grind off a fraction of a millimeter and induce some kind of spacer-related death wobble. Again, from what I've read elsewhere, it can be tapped back into place as is with a plastic or wooden mallet. Then the giant bolt goes back through. It is to be tightened it in increments, going from side to side.

What the torque numbers are for the switch and the giant bolt, I'll have to find out. Does anyone know?

Also, does anyone know if the neutral switch iuntil fall s exposed during the partial dis assembly required for an in-the-frame spline lube? If that's the case, I'll just add a little gear oil and park on newspaper until fall when I plan to lube the splines.

I suspect the neutral switch is of somewhat similar design as the leaky oil light switch I replaced last year. I couldn't tell whether the leak was through the wires or around the edge of the hard plastic sealant. In any case, the switches are old and exposed, so it figures they'd eventually give out. I'd be reluctant to modify them with any additional sealant for fear of doing something disastrous. A neutral switch modification-related death wobble, say.

Speaking of which, my bike will turn over 100,000 kilometers this tank of gas. The last 9,000 or so are mine. It runs like new. My hope is to keep it that way. The bleeding from the transmission must be staunched.

I thought about plugging the neutral switch myself. The starter switch uses it for a ground but it'd be easy to run the wire straight to the frame.

The worst thing about both of those switches is they use a pitch that's nigh impossible to find outside of a German car/bike shop. I think it was an M12 1.25 or something like that. If it's leaking and you're on the road I doubt you'll find a quick plug at the local hardware store.

What the torque numbers are for the switch and the giant bolt, I'll have to find out. Does anyone know?

Click to expand...

Torque numbers for the Neutral switch? Screw that.... When you install your new switch, wrap the threads with some plumbers tape and screw the switch in tight. What it's supposed to do is not fall out and not leak. I was dumb enough to pay a so-called "certified BMW mechanic" here in Santa Rosa, to install a new neutral switch for me and the next morning there was half a transmission's worth of gear lube on my garage floor. :eek1

Rather than take the bike back so that Mr Jackleg could screw something else up, I took a few minutes to do the job myself and it hasnt leaked a drop in the last six months. Whatever you do, don't have any work done on your Airhead, here in Santa Rosa!:fyyff

I don't think the newer and later switches are electrically incompatsble... I recall Anton saying that originally it was open one way, and closed opposite, and in later years, it was reversed, is this what you mean?
As far as torque goes, the switch and the engine mount bolts go up to snug and then a little bit. No numbers required,